A sheet processing apparatus may be provided downstream of an image forming device such as a copier, printer, or MFP (multi-functional peripheral) to perform post-processes such as sorting and stapling of printed sheets.
In such an apparatus, a sheet fed from a main body of an image-forming apparatus is received by a processing tray and stapled at the end of a bundle of the sheets on the processing tray. A movable loading tray capable of loading sheets or a bundle of sheets is provided at the downstream side in the conveying direction of the processing tray. The loading tray moves up and down depending on the loading amount. Sheets and a bundle of sheets subject to a post-processing such as stapling on the processing tray are ejected from the processing tray to the loading tray and then loaded on the loading tray. A plurality of sheets or a plurality of bundles of sheets is loaded on the loading tray sequentially by repeating such a process.
A force to eject from a processing tray to a loading tray is applied to a bundle of sheets that is being ejected. However, a friction occurs between the forward end of a bundle of sheets being ejected and a sheet on a loading tray, upon contacting the forward end of a sheet ejected from a processing tray to the top face of a sheet loaded on a loading tray. Therefore, the bundle of sheets may bend upwards in a convex state in the middle of ejecting, if the bundle of sheets comprises thin and frail sheets or a larger size of sheets. Incidence of a large bending of a bundle of sheets in the middle of ejection can lead to aligning trouble in which a position of a bundle of sheets cannot be aligned on a loading tray. Also, it may lead to ejection trouble in which the back end of the bended bundle of sheets remains on the processing tray.
Thus, a sheet processing apparatus that has fewer incidences of such aligning trouble and ejection trouble is desired.